Whatsoever an ass giveth against a wall, such he receiveth

“Whatsoever an ass giveth against a wall, such he receiveth” is a proverb about reciprocity: what one directs outward may return to oneself. In the Decameron, the phrase appears in a translator’s footnote attached to the tale of Ginevra, Bernabo Lomellini, and Ambrogiuolo of Piacenza. The note admits that the saying’s precise explanation is uncertain, while the tale’s ending and several other stories give its pattern a vivid social form: words and actions rebound upon those who set them in motion.

The proverb and its uncertain explanation

The footnote offers two possible ways to understand the proverb, depending on whether its terms refer to things or to people. Its likeliest explanation is deliberately humble and physical: an ass urinates against a wall, and the urine runs back toward it. The note presents this as a probability, not a settled meaning, and the uncertainty matters. The saying can work both as an image of literal return and as a general warning that conduct may bring consequences back upon its author.

Its placement gives the image a sharper narrative edge. At the close of the Ginevra story, Ambrogiuolo’s fraud is exposed, and he is executed by being anointed with honey and left to die amid the flies, wasps, and gadflies. The narrator concludes that the deceiver has ended up at the deceived person’s feet. The footnoted proverb belongs to the same moral orbit: deception does not remain a one-way act but turns back upon the deceiver, with a punishment as memorable as the fraud that preceded it.

A rebuke that changes its target

The proverb’s logic also illuminates stories in which a verbal blow is returned. When Guglielmo Borsiere visits Ermino de' Grimaldi, the Genoese gentleman asks what he might have painted in his new house’s salon that has never been seen before. Guglielmo answers, “Cause Liberality to be here depictured.” The request makes Ermino confront the quality he lacks. Ashamed, he promises to have Liberality painted and, more consequentially, changes his conduct: from then on he is described as Genoa’s most liberal and courteous gentleman, hospitable to strangers and citizens alike. Here the return is corrective rather than punitive: the pointed remark directs its force back at its hearer and produces a change in him.

A more openly retaliatory exchange occurs when Nonna de' Pulci is riding in Florence on Saint John’s Day with Antonio d'Orso and Dego della Ratta. Dego had paid Nonna’s husband with gilded silver coins in exchange for a night with the bishop’s niece, though she had not consented; the fraud and the husband’s sordidness had become public knowledge. When Antonio points Dego out to Nonna and asks whether she could conquer him, she answers that she might, but would want good money. Her reply turns the insinuation back upon the two men: Dego is shamed as the author of the earlier deceit, while Antonio is touched through his kinship with the wronged woman. Both ride away in embarrassed silence.

The measure of a witty answer

The framing remarks for the Sixth Day distinguish a sharp jest from a mere affront: a retort should bite like a sheep, not like a dog. The distinction makes the return of an insult a matter of judgment as well as force. A reply can answer an injury without simply repeating its violence; its success depends on whom it addresses, when it is spoken, and whether it exposes rather than merely wounds.

Guido Cavalcanti’s encounter with Messer Betto Brunelleschi and his companions offers another form of this reversal. Surrounded among the marble tombs near San Giovanni, Guido is taunted about his philosophical speculations and asked what he expects to accomplish if he discovers that God does not exist. He answers, “Gentlemen, you may say what you will to me in your own house,” then vaults over a tomb and escapes. The riders initially dismiss the reply, but Messer Betto interprets it for them: Guido has called the tombs the company’s house, implying that the ignorant and foolish are, beside learned men, like the dead. Once they understand the rebuke, they are abashed. As with Guglielmo’s counsel and Nonna’s retort, the apparent target of the encounter is not the only one made to feel its force.

A recurring pattern of return

These episodes do not all use the proverb, and their outcomes differ: Ermino reforms, Antonio and Dego fall silent, and Betto’s companions recognize their own foolishness. Together, however, they show how the collection repeatedly stages a return of force through speech. A question meant to display wealth reveals avarice; a jest that risks dishonoring a woman brings embarrassment upon its speakers; and a taunt becomes an occasion for the taunter’s own intellectual exposure. The proverb’s compact image is therefore apt beyond its uncertain literal explanation: actions and words can circle back, making their authors answerable to the very conduct they directed at others.